![4 R. K. Ramachandran et al.
equipped with localization devices, they may be deployed in GPS-denied environ-
ments (e.g., indoors or underground). Despite these constraints, the robots may be
required to map their environment in order to perform desired tasks. For instance, the
robots may need to identify target payloads to transport or obstacles and hazardous
regions to avoid. Since the robots will have limited sensing and computational capa-
bilities, it would not be feasible to implement existing techniques such as occupancy
grid mapping [24], simultaneous localization and mapping (SLAM) [21, 24], and
Probability Hypothesis Density (PHD) filtering [27] to address this problem.
Asaninitialsteptowardconstructingamapwithmetricinformation,wepresentan
automated method for computing the number of topological features in an unknown
domain from data obtained by a swarm of inexpensive robots with local sensing, no
inter-robot communication, and limited or no access to global position information.
The features represent obstacles or other regions of interest that robots do not pass
through. The data consist of robots’ position estimates and the covariance matrices of
these estimates, recorded by the robots during random exploration of the domain. The
robots collect this data autonomously and independently during their deployment,
without relying on input from a supervisory agent. We assume that after a set period
of time, the robots navigate to an easily identifiable landmark (e.g., a beacon), where
they transfer this data to a central computer. The computer then processes the data
from the entire swarm to extract a point cloud that covers the domain’s free space and
applies tools from Topological Data Analysis (TDA), namely persistent homology, to
identify the numbers of different types of topological features. Our approach scales
with the number of robots and is robust to the failure of a small portion of the swarm.
Although topological mapping has been extensively studied, TDA has only
recently been applied in robotics for environmental characterization. For a scenario
with a single robot, [7] presents a method for topological SLAM that encodes the
topology of the environment in a generalized Voronoi graph. Few works address the
problem of mapping an environment using a robotic swarm with limited sensing, no
inter-robot communication, and no global localization. In [19], we presented an opti-
mal control approach to mapping a GPS-denied environment with a robotic swarm
using a partial differential equation model of the swarm population dynamics. This
strategy works best when the domain contains only a few sparsely distributed fea-
tures, whereas the approach presented here can be applied to domains that are more
densely populated with features. In [20], the authors propose an algorithm that covers
the free space of the environment with robots and then constructs an approximate
generalized Voronoi graph of the covered region. This algorithm requires the robots
to communicate with a central server that commands their actions. In contrast, our
approach does not require a centralized decision maker during the robots’ operation.
Alternatively, [13] obtains a simplicial approximation of a region of interest as a
topological map using dual pairs of nerves that are constructed using relevant vis-
ibility and observation covers. Contrary to our strategy, [13] requires the robots to
have the ability to detect and maintain a record of landmarks in the domain, such as
obstacle corners and edges. The mapping approach in [8] is similar to ours in that it
generates a point cloud of the domain’s free region and uses persistent homology to
compute topological features in the environment. However, unlike our strategy, this](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-29-320.jpg)
![A Probabilistic Topological Approach to Feature Identification … 5
approach requires each robot to have an identification label that can be recognized
by other robots.
The paper is structured as follows. Section2 introduces the tools of TDA that
are used in our methodology. Section3 presents the problem statement and describes
assumptions about the robot capabilities and motion model. Our approach for extract-
ing topological features of the domain from the robots’ data is discussed in Sect.4.
Sects.5 and 6 validate our approach with simulations and multi-robot experiments,
respectively. Finally, Sect.7 concludes the paper and proposes future work.
2 Background
Topological Data Analysis (TDA) [5] is an emerging field that aims to provide algo-
rithmic and mathematical tools for studying topological and geometric attributes
of data. The fundamental idea underlying TDA is that data has an inherent shape
that encodes important information regarding the connectivity of the data and yields
insight into its global structure. TDA exploits the mathematical framework of alge-
braic topology [15], especially the concept of persistent homology [9], to characterize
the topological structure of data. In many applications, data is obtained as a point
cloud consisting of noisy samples of an intensity map in a Euclidean space. Prominent
topological features of a point cloud can be computed using TDA and presented in
the form of compact representations such as persistence diagrams [10] and barcode
diagrams [11]. TDA has been extensively applied to problems in computer vision
and image processing [23], sensor networks [6, 14], robotics [4, 18], localization
[22], and map comparison [3].
We provide a brief introduction to persistent homology, which is central to our
mapping methodology. More detailed treatments of the associated theory and com-
putations are given in [10, 16, 28]. Persistent homology is a method of analyzing the
correlation of homological information gathered across different scales. This tech-
nique enables the identification of topological features that are present over a large
range of scales, as opposed to those which are only temporarily present (short-scale
features). Homology is a robust tool that facilitates the study of global attributes of
spaces and functions from local computations on noisy data. A topological space T
can be associated with a collection of vector spaces called homology groups, denoted
by Hk(T), k = 0, 1, 2, ..., dim(T) − 1, each of which encodes a particular topologi-
cal feature of T. In persistent homology, these features are characterized using Betti
numbers, which are the ranks of the homology groups. These numbers are topo-
logical invariants. The kth
Betti number of T, denoted by βk, is the rank of Hk(T)
and represents the number of independent k-dimensional cycles in T. For example, if
T ⊂ R2
, then β0 is the number of connected components in T and β1 is the number of
holes in T. If T ⊂ R3
, then β0, β1, and β2 are the numbers of connected components,
tunnels, and voids in T, respectively.
In a typical TDA application, a finite set of samples from a space M is available.
These samples, along with the metric associated with M, comprise the point cloud](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-30-320.jpg)
![6 R. K. Ramachandran et al.
C of the space. In TDA, the metric is used to map C onto a collection of simplices
called a simplicial complex. Simplices are combinatorial objects constructed from
the subsets of C. A k-simplex σ = [v0, v1, ..., vk] is an ordered list of k +1 elements
{v0, v1, ..., vk} ∈ C, called vertices. The simplicial complex provides a discrete repre-
sentation of the underlying topological space using a combinatorial structure that can
be represented algebraically using linear operators (matrices). It is this combinatorial
structure that permits us to develop algorithms for homological computation. There
are various ways to build a simplicial complex from a point cloud. The simplest way
is to choose a parameter δ > 0 and add a k-simplex to the simplicial complex if
every vertex in the simplex is within a distance δ from every other. The simplicial
complex constructed in this manner is called the Vietoris–Rips complex [12] or Rips
complex for short, often denoted as Rips(C, δ).
For large datasets, the number of simplices in the simplicial complex can be enor-
mous, making the computations highly inefficient. We reduce the computational
requirements by choosing a subset of the point cloud consisting of landmark points,
denoted by L ⊂ C, as vertices for the Rips complex. These landmark points were
selected using a greedy inductive selection process called a sequential max-min algo-
rithm[1]. Inorder tocomputepersistent Betti numbers, werequireafiltration, defined
as a family of Rips(C, δ) parametrized by δ such that Rips(C, δ1) ⊆ Rips(C, δ2)
for all δ1 > 0, δ2 > 0 where δ1 ≤ δ2.
The persistent topological features of T over multiple values of δ can be identified
using a barcode diagram, which is a graphical representation of Hk(T) in terms of the
homology generators. A barcode plots a set of horizontal line segments on a graph
whose x-axis spans a range of δ values and whose y-axis depicts an arbitrary ordering
of homology generators. The numbers of arrows in the barcode for dimension 0
and dimension 1 indicate the numbers of connected components and features in
the domain, respectively. A barcode diagram can be computed automatically using
algorithms that find the homology generators of the homology that is constructed on
a point cloud. Figure1 illustrates a barcode diagram that is obtained from an example
point cloud.
3 Problem Statement
We consider a scenario in which N robots are deployed into a bounded, unknown,
GPS-denied 2D environment in order to collect data that can be used to determine
the number of topological features in the domain. The robots have local sensing
capabilities and can identify features and other robots at distances within their sensing
range to perform collision avoidance maneuvers. Each robot is equipped with a
compass and wheel encoders, which enable it to estimate its position and orientation
with uncertainty.
The robots perform correlated random walks in the domain, avoiding features and
other robots. During its motion, each robot estimates its position in a global reference
frame using its onboard odometry and a Kalman filter. At fixed time intervals, the](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-31-320.jpg)
![A Probabilistic Topological Approach to Feature Identification … 7
Fig. 1 An example barcode diagram of a filtration formed from a Rips complex. βk(δi ) is the
number of horizontal segments in the barcode for Hk(T) that intersect the dashed line at δ = δi
robot records its estimated position and the covariance matrix corresponding to the
uncertainty of the estimate. After a time span T , all robots travel to a common location
where their stored data is retrieved and processed. We assume that T is sufficiently
large for the robots to thoroughly cover the domain and that the robots have sufficient
memory to store the data that they obtain during their deployment.
The robots follow the motion model described in [25]. Each robot has a con-
stant translational speed v and an orientation θ(t) at time t with respect to a global
frame. We define a robot’s velocity vector at time t as V(t) = [vx (t), vy(t)]T
=
[v cos(θ(t)), v sin(θ(t))]T
and its position vector as X(t) = [x(t), y(t)]T
. The
displacement of a robot over a time step Δt is given by
X(t + Δt) = X(t) + V(t)Δt + W(t), (1)
where W(t) ∈ R2
is a vector of independent, zero-mean normal random variables
that are generated at time t to model the randomness in the robot’s motion due to
sensor and actuator noise. At the beginning of a time step, each robot generates a
random number between 0 and 1. If this number is below a predefined threshold
pth, the robot randomly chooses a new θ(t) ∈ [−π, π]. At time t = 0, the start of
a deployment, each robot is assigned the parameters v and pth and obtains accurate
measurements of its position X(0) and orientation θ(0).
We consider two types of scenarios. In Type I scenarios, robots receive accu-
rate estimates of their global positions when they are close to the boundary of the
domain. For example, robots on the exterior of a building will have access to GPS
measurements that are unavailable to robots inside. In Type II scenarios, robots do
not receive global position updates anywhere in the domain, which may for instance
be located underground or underwater.](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-32-320.jpg)
![girls who go abroad for education are all sent to the convents of France,
but many boys are now sent to schools in the States, especially for a
technical education. Those who do go come back enthusiastic over the
United States, and many of them bring back American wives, much to
the discomfiture of the parents.
An aristocracy exists which can yet be traced, and it is an aristocracy
of wealth. It divides, with a sharp distinction, the aristocracy from the
labouring element. It is perhaps unreasonable to expect the classes
developed by a monarchical form of government to disappear so soon,
for the spirit was imbued in the dozen or more generations preceding
the present one. Among that class it was considered a disgrace to labour
with one’s hands, and this fact has made politics and the holding of
political positions a profession. This weakness in politics is, in my
opinion, one of the evils of Brazil. It becomes a business and a passion
with the men, even in a more intense degree than in our own land. The
young man must first secure the title of doctor, and every professional
man, physician, lawyer, civil engineer, teacher, etc., receives this title.[1]
Then he must obtain some government appointment. Finally, when his
own prestige becomes great enough, he seeks election to some office.
To politics can be blamed the lack of advancement in many lines.
Said one of the wealthiest and most progressive business men in Rio
de Janeiro, himself a Brazilian, to me: “Politics are the curse of the
country. It is all words and delay. The politicians like to talk about their
great country. They boast that the Amazon is the greatest river in the
world, so large that the Mississippi dwindles into an insignificant stream
in comparison; that Rio is the finest harbour in the world and capable of
floating all the navies in existence; and that Brazil has the greatest
undeveloped natural resources in the world. When any of the resources
are developed, however, it is not these men who help to do it, but it is
the foreigner who sees the opportunity and grasps it. Congress meets
and talks politics, instead of passing the necessary legislation. They
want to subsidize everything instead of giving competition a chance. I
am past sixty years of age, and it has been that way ever since I can
remember.” This is quite a severe arraignment of the evils of politics, but
it was exemplified during my own visit. The regular session of Congress
came to an end in October, and a special session was at once convened,](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-47-320.jpg)
![thousand seven hundred and fifty-four, and an attendance of sixty-nine
thousand four hundred and thirty-two. Private primary schools have an
enrolment of one hundred and ten thousand eight hundred and forty-
one, and an attendance of eighty-one thousand and sixty-six. Of the
three hundred and twenty-seven secondary institutions twenty-nine are
public and two hundred and ninety-eight under private control, the
former having an enrolment of four thousand and the latter of twenty-
six thousand two hundred and fifty-eight. No figures of the actual
attendance at these institutions were given, but it would probably not be
much less than the enrolment. If these government figures are correct,
and the population is twenty million five hundred and fifteen thousand
as claimed, in that same report, then scarcely three per cent. of the
population may be regarded as enjoying school privileges. This estimate
takes on new significance when one considers that the proportion of
rural population is very high, as compared with the entire population,
and shows how much less the facilities are in those sections. In the
Federal District, for instance, which includes the city of Rio de Janeiro,
and where the population is almost entirely urban, there is an estimated
population of eight hundred and fifty-eight thousand, and a school
enrolment of sixty-one thousand nine hundred and thirty-three. In the
state of Alagoas, on the other hand, with an almost equal population,
and where it is altogether rural with the exception of a few coast towns,
there is a school enrolment of only fourteen thousand and ninety-two.
The state of Pernambuco, with only one town of any size, and that the
capital, has a school enrolment of only twenty-two thousand eight
hundred and fifty-two, in a reported population of one million three
hundred and ten thousand. More comparisons might be made, but with
these explanations the reader can figure them out from the table.[2]](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-53-320.jpg)
![Portuguese writers are prolific. Few countries have produced more
literature, compared with the number who speak the language, than
Portugal and Brazil. The Portuguese language is especially rich in
expression, and is said to be the nearest to the classic Latin of any living
dialect. It lends itself easily to poetic expression, and there have been
many poets. The Brazilians are fond of elaborate and flowery
expressions, and this verboseness and ornate form of expression runs
through their literature and public speaking. At the commencement
exercises mentioned above the addresses of some of the graduates
were most elaborate. Where an American graduate would have started
out with “Ladies and Gentlemen,” and perhaps have added “our dear
professors and honourable trustees,” the Brazilian youth took several
minutes to make his introductory remarks, and pass around his
compliments to the professors and other dignitaries who were on the
stage. No one was omitted in the general round of compliments.
Impromptu poems spring up on every and all occasions, and the recent
visit of a high state official of the United States prompted more than one
poetic effusion, many of which were fortunately suppressed by the
committees in charge of the festivities.
Brazil has produced a number of eminent writers. The best known,
and perhaps most widely loved of all, is Gonçalves Diaz, who has been
called the Longfellow of Brazil. He died nearly a half century ago, but his
memory has been honoured by monuments and streets named in his
honour, and his name has been kept green by continuous quotations
from his writings. The “Song of the Exile,” written by him, has been
called the “Home, Sweet Home” of the Brazilians, and is said to be
quoted more than any other poem in the language. Says Mrs. Wright:[3]
“No translation has ever been made which in any sense reveals the
exquisite delicacy of touch in the original, or its plaintive rhythmic
melody, though many attempts have been made to put it into English
and other languages. Throughout the six stanzas of which it is
composed, the little poem voices a heart cry of homesickness. After
recounting, with childlike simplicity, the charm of his native land, its
palm trees, and the sweet-voiced Sabiá, the favourite songbird of Brazil,
he prays with touching pathos to be spared to return, that he may once
more see its glorious palms and hear the Sabiá sing.” Diaz had received
a good education in Portugal, and became a professor of history in the](https://image.slidesharecdn.com/34295-250609143638-724f4d3d/85/Distributed-Autonomous-Robotic-Systems-Roderich-Gross-61-320.jpg)
Distributed Autonomous Robotic Systems Roderich Groß
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- 4. Distributed Autonomous Robotic Systems Roderich Groß · Andreas Kolling Spring Berman · Emilio Frazzoli Alcherio Martinoli · Fumitoshi Matsuno Melvin Gauci Editors The 13th International Symposium Springer Proceedings in Advanced Robotics 6 Series Editors: Bruno Siciliano · Oussama Khatib
- 5. Springer Proceedings in Advanced Robotics Series editors Prof. Bruno Siciliano Dipartimento di Ingegneria Elettrica e Tecnologie dell’Informazione Università degli Studi di Napoli Federico II Via Claudio 21, 80125 Napoli Italy E-mail: siciliano@unina.it Prof. Oussama Khatib Robotics Laboratory Department of Computer Science Stanford University Stanford, CA 94305-9010 USA E-mail: khatib@cs.stanford.edu Editorial Advisory Board Gianluca Antonelli, University of Cassino, Italy Dieter Fox, University of Washington, USA Kensuke Harada, Osaka University, Japan M. Ani Hsieh, University of Pennsylvania, USA Torsten Kröger, Karlsruhe Institute of Technology, Germany Dana Kulić, University of Waterloo, Canada Jaehung Park, Seoul National University, South Korea 6
- 6. More information about this series at http://www.springer.com/series/15556
- 7. Roderich Groß • Andreas Kolling Spring Berman • Emilio Frazzoli Alcherio Martinoli • Fumitoshi Matsuno Melvin Gauci Editors Distributed Autonomous Robotic Systems The 13th International Symposium 123
- 8. Editors Roderich Groß Department of Automatic Control and Systems Engineering University of Sheffield Sheffield UK Andreas Kolling Department of Automatic Control and Systems Engineering University of Sheffield Sheffield UK Spring Berman School for Engineering of Matter, Transport and Energy (SEMTE) Arizona State University Tempe, AZ USA Emilio Frazzoli Massachusetts Institute of Technology Cambridge, MA USA Alcherio Martinoli ENAC, IIE, DIAL École Polytechnique Fédérale de Lausanne (EPFL) Lausanne Switzerland Fumitoshi Matsuno Department of Mechanical Engineering and Science Kyoto University Kyoto Japan Melvin Gauci Wyss Institute for Biologically Inspired Engineering Harvard University Wyss Institute for Biologically Inspired Cambridge, MA USA ISSN 2511-1256 ISSN 2511-1264 (electronic) Springer Proceedings in Advanced Robotics ISBN 978-3-319-73006-6 ISBN 978-3-319-73008-0 (eBook) https://doi.org/10.1007/978-3-319-73008-0 Library of Congress Control Number: 2017962037 © Springer International Publishing AG 2018 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Printed on acid-free paper This Springer imprint is published by the registered company Springer International Publishing AG part of Springer Nature The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland
- 9. Foreword Robots! Robots on Mars and in oceans, in hospitals and homes, in factories and schools; robots fighting fires, making goods and products, saving time and lives. Robots today are making a considerable impact from industrial manufacturing to healthcare, transportation, and exploration of the deep space and sea. Tomorrow, robots will become pervasive and touch upon many aspects of modern life. The Springer Tracts in Advanced Robotics (STAR) was launched in 2002 with the goal of bringing to the research community the latest advances in the robotics field based on their significance and quality. During the past 15 years, the STAR series has featured publication of both monographs and edited collections. Among the latter, the proceedings of thematic symposia devoted to excellence in robotics research, such as ISRR, ISER, FSR, and WAFR, have been regularly included in STAR. The expansion of our field as well as the emergence of new research areas has motivated us to enlarge the pool of proceedings in the STAR series in the past few years. This has ultimately led to launching a sister series in parallel to STAR. The Springer Proceedings in Advanced Robotics (SPAR) is dedicated to the timely dissemination of the latest research results presented in selected symposia and workshops. This volume of the SPAR series brings the proceedings of the thirteenth edition of the DARS symposium on Distributed Autonomous Robotic Systems, whose proceedings have been previously published within STAR. This symposium took place at the Natural History Museum in London from November 7th to 9th, 2016. The volume edited by Roderich Groß, Andreas Kolling, Spring Berman, Emilio Frazzoli, Alcherio Martinoli, Fumitoshi Matsuno, and Melvin Gauci contains 47 scientific contributions organized in seven chapters. This collection focuses on robotic exploration, modular and swarm robotics, multi-robot control, estimation, planning, and applications. v
- 10. From its excellent technical program to its warm social interaction, DARS culminates with this unique reference on the current developments and new advances in distributed autonomous robotic systems—a genuine tribute to its contributors and organizers! Naples, Italy Bruno Siciliano Stanford, CA, USA Oussama Khatib November 2017 SPAR Editors vi Foreword
- 11. Preface These proceedings contain the papers presented at DARS 2016, the 13th International Symposium on Distributed Autonomous Robotic Systems, which was held at the Natural History Museum in London, UK, from November 7th to 9th, 2016. The goal of DARS is to provide a forum for scientific advances in the theory and practice of distributed autonomous robotic systems. Distributed robotics is an interdisciplinary and rapidly growing area, combining research in computer science, communication and control systems, and electrical and mechanical engineering. Distributed robotic systems can autonomously solve complex problems while operating in highly unstructured real-world environments. They are expected to play a major role in addressing future societal needs, for example, by improving environmental impact assessment, food supply, transportation, manufacturing, security, and emergency and rescue services. Building upon previous editions, the symposium presented a strong and varied technical program. We received a record 120 paper submissions—a testament to the thriving and growing nature of the field. The review process was overseen by the Program Chairs. Each paper was reviewed by at least three reviewers. Moreover, each paper received a final evaluation by a Program Chair. We would like to thank all members of the Program Committee as well as the additional referees for their diligent and constructive reviews—a crucial element for upholding the high tech- nical standard of DARS. The review process yielded 47 papers to be included in the symposium, corresponding to an acceptance rate of 39%. Of the 47 papers, 30 papers were presented orally, and 17 papers were presented as posters. The method of presentation was chosen not only based on the quality of each paper, but also on content in order to ensure a well-balanced oral track, which is of interest to most of the attendees. Additionally, the papers for oral presentation were divided into seven thematic areas, namely Distributed Coverage and Exploration, Multi-Robot Control, Multi-Robot Estimation, Multi-Robot Planning, Modular Robots and Smart Materials, Swarm Robotics, and Multi-Robot Systems in Applications. All 47 accepted papers are included in these proceedings. The program also featured four invited keynote addresses by researchers who are making a lasting contribution to science and robotics: “Material-Integrated vii
- 12. Intelligence for Robot Autonomy” by Nikolaus Correll (University of Colorado Boulder, USA), “Coordination, Cooperation and Collaboration in Multi-Robot Systems” by Vijay Kumar (University of Pennsylvania, USA), “Go to the Bee and Be Wise: Swarm Engineering Inspired by House-Hunting Honeybees” by James Marshall (University of Sheffield, UK), and “Robust Human Control of Multi-Robot Swarms” by Katia Sycara (Carnegie Mellon University, USA). The abstracts of these four keynote addresses are included in the proceedings. This edition of DARS included three awards: Best Paper, Best Application Paper, and Best Poster. The awards committee was chaired by Michael Rubenstein (Northwestern University, USA) and included Melvin Gauci (Harvard University, USA), Sabine Hauert (Bristol University, UK), and Bahar Haghighat (EPFL, Switzerland). For the Best Paper award, the Program Chairs nominated six papers as finalists from among all the accepted papers based on the reports and award nominations by the referees, as well as on the revised contributions included in the digital proceedings. The final decision also took into account the presentation quality at the symposium. The Best Paper award went to “Robust Coordinated Aerial Deployments for Theatrical Applications Given Online User Interaction via Behavior Composition” by Elen Cappo et al. The Best Application Paper award was sponsored by the Institution of Engineering and Technology. All orally-presented papers were eligible for this award, and the decision took into account the degree to which the work addressed problems of practical implemen- tation, and the quality of the presentation. This award went to “Multi-Swarm Infrastructure for Swarm Versus Swarm Experimentation” by Duane Davis et al. All posters were eligible for the Best Poster award, and the decision was based on the quality of the work and the poster presentation. This award went to “Vertex: A New Distributed Underwater Robotic Platform for Environmental Monitoring” by Felix Schill et al. We would like to thank everyone involved in making DARS 2016 a success, including VICON Motion Systems (DARS 2016 Platinum Sponsor), RS Components (DARS 2016 Gold Sponsor), the Advisory Committee, the Program Committee and additional referees, the Organizing Committee, and all the authors of all submitted papers. Finally, we would like to thank the local organization team, in particular Ana Macintosh and Stefan M. Trenkwalder. Sheffield, UK Roderich Groß July 2017 Andreas Kolling Spring Berman Emilio Frazzoli Alcherio Martinoli Fumitoshi Matsuno Melvin Gauci viii Preface
- 13. Organization General Chair Roderich Groß, The University of Sheffield, UK General Co-Chair Andreas Kolling, iRobot, USA Technical Program Co-Chairs Spring Berman, Arizona State University, USA Emilio Frazzoli, MIT, USA Alcherio Martinoli, EPFL, Switzerland Fumitoshi Matsuno, Kyoto University, Japan Publication Chair Melvin Gauci, Harvard University, USA Publicity Chair Sabine Hauert, University of Bristol, UK Local Organization Team Louise A. Caffrey, The University of Sheffield, UK Ana MacIntosh, The University of Sheffield, UK Stefan M. Trenkwalder, The University of Sheffield, UK Advisory Committee Hajime Asama, University of Tokyo, Japan Marcelo H. Ang, National University of Singapore, Singapore Tamio Arai, University of Tokyo, Japan Raja Chatila, UPMC, France Gregory S. Chirikjian, Johns Hopkins University, USA Young-Jo Cho, ETRI, Republic of Korea Nak Young Chong, JAIST, Japan Nikolaus Correll, University of Colorado Boulder, USA ix
- 14. Rüdiger Dillmann, KIT, Germany Toshio Fukuda, Nagoya University, Japan Maria Gini, University of Minnesota, USA M. Ani Hsieh, University of Pennsylvania, USA Alcherio Martinoli, EPFL, Switzerland Francesco Mondada, EPFL, Switzerland Lynne E. Parker, University of Tennessee, USA Program Committee William Agassounon, Textron Defense Systems Inc., USA Antonio P. Aguiar, University of Porto, Portugal Rachid Alami, LAAS-CNRS, France Javier Alonso-Mora, MIT, USA Francesco Amigoni, Polytechnic University of Milan, Italy Marcelo H. Ang, National University of Singapore, Singapore Adrian Arfire, EPFL, Switzerland Ryo Ariizumi, Nagoya University, Japan Filippo Arrichiello, University of Cassino and Southern Lazio, Italy Masoud Asadpour, University of Tehran, Iran Shun-ichi Azuma, Kyoto University, Japan Nicola Basilico, University of Milan, Italy Meysam Basiri, EPFL, Switzerland Jacob Beal, Raytheon BBN Technologies, USA Kostas Bekris, Rutgers University, USA Gerardo Beni, University of California, Riverside, USA Sarah Bergbreiter, University of Maryland, USA Navneet Bhalla, Harvard University, USA Subhrajit Bhattacharya, University of Pennsylvania, USA Mauro Birattari, Université Libre de Bruxelles, Belgium Nicolas Bredeche, Pierre and Marie Curie University, France Andreas Breitenmoser, University of Southern California, USA Zack J. Butler, Rochester Institute of Technology, USA Stefano Carpin, University of California, Merced, USA Luiz Chaimowicz, Federal University of Minas Gerais, Brazil Han-Lim Choi, KAIST, Republic of Korea Anders L. Christensen, University Institute of Lisbon, Portugal Timothy H. Chung, DARPA, USA Brian Coltin, Carnegie Mellon University, USA Nikolaus Correll, University of Colorado Boulder, USA Jorge Cortés, University of California, San Diego, USA Raffaello D’Andrea, ETH Zurich, Switzerland Philip Dames, Temple University, USA Karthik Dantu, SUNY Buffalo, USA x Organization
- 15. Prithviraj Dasgupta, University of Nebraska Omaha, USA Carrick Detweiler, University of Nebraska Lincoln, USA Gianni A. Di Caro, IDSIA USI, Switzerland Rüdiger Dillmann, KIT, Germany Dimos Dimarogonas, KTH, Sweden Clare Dixon, University of Liverpool, USA Marco Dorigo, Université Libre de Bruxelles, Belgium Takahiro Endo, Kyoto University, Japan William C. Evans, Google, USA Alessandro Farinelli, University of Verona, Italy Eliseo Ferrante, University of Leuven, Belgium Rafael Fierro, The University of New Mexico, USA Robert Fitch, The University of Sydney, Australia Ryusuke Fujisawa, Hachinohe Institute of Technology, Japan Rui Fukui, University of Tokyo, Japan Simon Garnier, New Jersey Institute of Technology, USA Andrea Gasparri, Roma Tre University, Italy Melvin Gauci, Harvard University, USA Veysel Gazi, Istanbul Kemerburgaz University, Turkey Katie Genter, University of Texas Austin, USA Maria Gini, University of Minnesota, USA Heiko Hamann, University of Paderborn, Germany Kiyohiko Hattori, NICT, Japan Sabine Hauert, University of Bristol, UK Tomohisa Hayakawa, Tokyo Institute of Technology, Japan Geoffrey Hollinger, Oregon State University, USA Satoshi Hoshino, Utsunomiya University, Japan Jonathan P. How, MIT, USA M. Ani Hsieh, University of Pennsylvania, USA Hiroyuki Iizuka, Hokkaido University, Japan Volkan Isler, University of Minnesota, USA Yoshiaki Katada, Setsunan University, Japan Takashi Kawakami, Hokkaido University of Science, Japan Mirko Kovac, Imperial College London, UK Masao Kubo, National Defense Academy, Japan Daisuke Kurabayashi, Tokyo Institute of Technology, Japan Haruhisa Kurokawa, AIST, Japan Konstantinos J. Kyriakopoulos, National Technical University of Athens, Greece Dongjun Lee, Seoul national University, Republic of Korea Somchaya Liemhetcharat, Uber Advanced Technologies Center, USA Pedro U. Lima, University of Lisbon, Portugal Ali Marjovi, EPFL, Switzerland Lino Marques, University of Coimbra, Portugal Fulvio Mastrogiovanni, University of Genova, Italy Organization xi
- 16. Nathan Michael, Carnegie Mellon University, USA Dejan Milutinovic, University of California, Santa Cruz, USA Melanie Moses, The University of New Mexico, USA Masaaki Nagahara, Kyoto University, Japan Radhika Nagpal, Harvard University, USA Toru Namerikawa, Keio University, Japan Nils Napp, SUNY Buffalo, USA Daniele Nardi, Sapienza University of Rome, Italy Keitaro Naruse, University of Aizu, Japan Iñaki Navarro, EPFL, Switzerland Giuseppe Notarstefano, University of Salento, Italy Michael Novitzky, Georgia Institute of Technology, USA Shinsuke Oh-hara, University of Yamanashi, Japan Kazuhiro Ohkura, Hiroshima University, Japan Derek Paley, University of Maryland, USA Lucia Pallottino, University of Pisa, Italy Antonio Pascoal, University of Lisbon, Portugal Marco Pavone, Stanford University, USA José Pereira, EPFL, Switzerland Kirstin H. Petersen, Cornell University, USA Hemma Philamore, University of Bristol, UK Luciano C. A. Pimenta, Federal University of Minas Gerais, Brazil Carlo Pinciroli, Ecole Polytechnique de Montréal, Canada Amanda Prorok, University of Pennsylvania, USA Subramanian Ramamoorthy, The University of Edinburgh, UK Andreagiovanni Reina, The University of Sheffield, UK Ioannis Rekleitis, University of South Carolina, USA Paolo Remagnino, Kingston University London, UK Alessandro Renzaglia, LAAS CNRS, France Paolo Robuffo Giordano, IRISA/INRIA Rennes, France Michael Rubenstein, Northwestern University, USA Lorenzo Sabattini, University of Modena and Reggio Emilia, Italy Brian Sadler, US Army Research Laboratory, USA Erol Sahin, Middle East Technical University, Turkey Kazunori Sakurama, Tottori University, Japan Ketan Savla, University of Southern California, USA Thomas Schmickl, University of Graz, Austria Mac Schwager, Stanford University, USA Iman Shames, University of Melbourne, Australia Dylan A. Shell, Texas A&M University, USA Wei-Min Shen, University of Southern California, USA Tomohiro Shirakawa, National Defense Academy of Japan, Japan Stephen L. Smith, University of Waterloo, Canada Paolo Stegagno, Cornell University, USA xii Organization
- 17. Kasper Stoy, IT University of Copenhagen, Denmark Ken Sugawara, Tohoku Gakuin University, Japan Ikuo Suzuki, Kitami Institute of Technology, Japan Keiki Takadama, The University of Electrocommunications, Japan Herbert G. Tanner, University of Delaware, USA Danilo Tardioli, University Center of Defense, Spain Guy Theraulaz, Paul Sabatier University and CNRS, France Jonathan Timmis, University of York, UK Vito Trianni, ISTC CNR, Italy Elio Tuci, Aberystwyth University, UK Kazuki Umemoto, Kanagawa University, Japan Richard T. Vaughan, Simon Fraser University, Canada Rodrigo Ventura, University of Lisbon, Portugal Richard Voyles, Purdue University, USA Justin Werfel, Harvard University, USA Kazuaki Yamada, Toyo University, Japan Masahito Yamamoto, Hokkaido University, Japan Toshiyuki Yasuda, Hiroshima University, Japan Jingjin Yu Rutgers, University, USA Ikemoto Yusuke, Meijo University, Japan Uwe R. Zimmer, Australian National University, Australia Additional Referees Charuvahan Adhivarahan Jacopo Banfi Florian Berlinger Barbara Bruno Levi DeVries Sedat Dogru Kevin Eckenhoff Elizabeth Esterly Andres Faina Boris Gromov Bahar Haghighat Christoph Hintz Lucas Janson Matthew Kelly Yara Khaluf Jose Marcio Luna Massimo Mecella Michael Otte Alyssa Pierson Ragesh K. Ramachandran Daniel Selvaratnam Organization xiii
- 18. Sara Spedicato Khalil Taheri Stefan M. Trenkwalder Constantinos Vrohidis Jonathan West Sean Wilson Indrajeet Yadav Dingjiang Zhou Saeed Ahmadizadeh Cenk Baykal Dimitris Boskos Alessio Capitanelli Krishna Doddapaneni Miguel Duarte Iñaki Esnaola Mark Fabbro Jorge Gomes Meng Guo Shahab Heshmati-Alamdari Frank Imeson Aris Kanellopoulos Monroe Kennedy Ganesh Kumar Yoshiyuki Matsumura Ivano Notarnicola Cammy Peterson Hasan Poonawala Philipp Schillinger Wenceslao Shaw-Cortez Adam Stager Andrea Testa Andrea Vanzo Zijian Wang Michael Whitzer Peter Wurman Michael Zavlanos xiv Organization
- 19. Contents Part I Distributed Coverage and Exploration A Probabilistic Topological Approach to Feature Identification Using a Stochastic Robotic Swarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Ragesh K. Ramachandran, Sean Wilson and Spring Berman Communication-Restricted Exploration for Search Teams . . . . . . . . . . . 17 Elizabeth A. Jensen, London Lowmanstone and Maria Gini From Ants to Birds: A Novel Bio-Inspired Approach to Online Area Coverage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Luca Giuggioli, Idan Arye, Alexandro Heiblum Robles and Gal A. Kaminka Information Based Exploration with Panoramas and Angle Occupancy Grids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Daniel Mox, Anthony Cowley, M. Ani Hsieh and C. J. Taylor Multirobot Persistent Patrolling in Communication-Restricted Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Marta Romeo, Jacopo Banfi, Nicola Basilico and Francesco Amigoni Part II Multi-Robot Control A Comparative Study of Collision Avoidance Algorithms for Unmanned Aerial Vehicles: Performance and Robustness to Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Steven Roelofsen, Denis Gillet and Alcherio Martinoli A Decentralized Control Strategy for Resilient Connectivity Maintenance in Multi-robot Systems Subject to Failures . . . . . . . . . . . . 89 Cinara Ghedini, Carlos H. C. Ribeiro and Lorenzo Sabattini xv
- 20. Chase Your Farthest Neighbour. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Rotem Manor and Alfred M. Bruckstein OuijaBots: Omnidirectional Robots for Cooperative Object Transport with Rotation Control Using No Communication . . . . . . . . . 117 Zijian Wang, Guang Yang, Xuanshuo Su and Mac Schwager Persistent Multi-robot Formations with Redundancy . . . . . . . . . . . . . . . 133 Alyxander Burns, Bernd Schulze and Audrey St. John Triangular Networks for Resilient Formations . . . . . . . . . . . . . . . . . . . . 147 David Saldaña, Amanda Prorok, Mario F. M. Campos and Vijay Kumar Part III Multi-Robot Estimation Construction of Optimal Control Graphs in Multi-robot Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Gal A. Kaminka, Ilan Lupu and Noa Agmon Decision-Making Accuracy for Sensor Networks with Inhomogeneous Poisson Observations . . . . . . . . . . . . . . . . . . . . . . 177 Chetan D. Pahlajani, Indrajeet Yadav, Herbert G. Tanner and Ioannis Poulakakis Distributed Laplacian Eigenvalue and Eigenvector Estimation in Multi-robot Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 Mehran Zareh, Lorenzo Sabattini and Cristian Secchi Distributed Object Characterization with Local Sensing by a Multi-robot System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Golnaz Habibi, Sándor P. Fekete, Zachary Kingston and James McLurkin Optical Wireless Communications for Heterogeneous DARS . . . . . . . . . 219 Patricio J. Cruz, Christoph Hintz, Jonathan West and Rafael Fierro Part IV Multi-Robot Planning Bundling Policies for Sequential Stochastic Tasks in Multi-robot Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 Changjoo Nam and Dylan A. Shell Decomposition of Finite LTL Specifications for Efficient Multi-agent Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 Philipp Schillinger, Mathias Bürger and Dimos V. Dimarogonas Informative Path Planning and Mapping with Multiple UAVs in Wind Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 Doo-Hyun Cho, Jung-Su Ha, Sujin Lee, Sunghyun Moon and Han-Lim Choi xvi Contents
- 21. Multi-robot Informative and Adaptive Planning for Persistent Environmental Monitoring . . . . . . . . . . . . . . . . . . . . . . . . 285 Kai-Chieh Ma, Zhibei Ma, Lantao Liu and Gaurav S. Sukhatme The Effectiveness Index Intrinsic Reward for Coordinating Service Robots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Yinon Douchan and Gal A. Kaminka United We Move: Decentralized Segregated Robotic Swarm Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 Fabrício R. Inácio, Douglas G. Macharet and Luiz Chaimowicz Part V Modular Robots and Smart Materials A Rule Synthesis Algorithm for Programmable Stochastic Self-assembly of Robotic Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329 Bahar Haghighat and Alcherio Martinoli Distributed Adaptive Locomotion Learning in ModRED Modular Self-reconfigurable Robot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345 Ayan Dutta, Prithviraj Dasgupta and Carl Nelson Distributed Camouflage for Swarm Robotics and Smart Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359 Yang Li, John Klingner and Nikolaus Correll Evo-Bots: A Simple, Stochastic Approach to Self-assembling Artificial Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373 Juan A. Escalera, Matthew J. Doyle, Francesco Mondada and Roderich Groß Geometrical Study of a Quasi-spherical Module for Building Programmable Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387 Benoît Piranda and Julien Bourgeois HyMod: A 3-DOF Hybrid Mobile and Self-Reconfigurable Modular Robot and its Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401 Christopher Parrott, Tony J. Dodd and Roderich Groß Network Characterization of Lattice-Based Modular Robots with Neighbor-to-Neighbor Communications . . . . . . . . . . . . . . . . . . . . . 415 André Naz, Benoît Piranda, Thadeu Tucci, Seth Copen Goldstein and Julien Bourgeois Part VI Swarm Robotics Decentralized Progressive Shape Formation with Robot Swarms . . . . . . 433 Carlo Pinciroli, Andrea Gasparri, Emanuele Garone and Giovanni Beltrame Contents xvii
- 22. Discovery and Exploration of Novel Swarm Behaviors Given Limited Robot Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447 Daniel S. Brown, Ryan Turner, Oliver Hennigh and Steven Loscalzo Effects of Spatiality on Value-Sensitive Decisions Made by Robot Swarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461 Andreagiovanni Reina, Thomas Bose, Vito Trianni and James A. R. Marshall Emergence and Inhibition of Synchronization in Robot Swarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475 Fernando Perez-Diaz, Stefan M. Trenkwalder, Rüdiger Zillmer and Roderich Groß Evolving Behaviour Trees for Swarm Robotics . . . . . . . . . . . . . . . . . . . 487 Simon Jones, Matthew Studley, Sabine Hauert and Alan Winfield Evolving Group Transport Strategies for e-Puck Robots: Moving Objects Towards a Target Area . . . . . . . . . . . . . . . . . . . . . . . . 503 Muhanad H. Mohammed Alkilabi, Aparajit Narayan, Chuan Lu and Elio Tuci From Formalised State Machines to Implementations of Robotic Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517 Wei Li, Alvaro Miyazawa, Pedro Ribeiro, Ana Cavalcanti, Jim Woodcock and Jon Timmis Human Responses to Stimuli Produced by Robot Swarms - the Effect of the Reality-Gap on Psychological State . . . . . . . 531 Gaëtan Podevijn, Rehan O’Grady, Carole Fantini-Hauwel and Marco Dorigo Localization of Inexpensive Robots with Low-Bandwidth Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545 Shiling Wang, Francis Colas, Ming Liu, Francesco Mondada and Stéphane Magnenat Modelling Mood in Co-operative Emotional Agents . . . . . . . . . . . . . . . . 559 Joe Collenette, Katie Atkinson, Daan Bloembergen and Karl Tuyls Programmable Self-disassembly for Shape Formation in Large-Scale Robot Collectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573 Melvin Gauci, Radhika Nagpal and Michael Rubenstein xviii Contents
- 23. Towards Differentially Private Aggregation of Heterogeneous Robots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587 Amanda Prorok and Vijay Kumar Part VII Multi-Robot Systems in Applications Construction Planning for a Modularized Rail Structure: Type Selection of Rail Structure Modules and Dispatch Planning of Constructor Robots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605 Rui Fukui, Yuta Kato, Gen Kanayama, Ryo Takahashi and Masayuki Nakao Distributed Convolutional Neural Networks for Human Activity Recognition in Wearable Robotics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619 Dana Hughes and Nikolaus Correll Formation Control of a Drifting Group of Marine Robotic Vehicles . . . 633 Nicholas R. Rypkema and Henrik Schmidt Multi-swarm Infrastructure for Swarm Versus Swarm Experimentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649 Duane T. Davis, Timothy H. Chung, Michael R. Clement and Michael A. Day Robust Coordinated Aerial Deployments for Theatrical Applications Given Online User Interaction via Behavior Composition . . . . . . . . . . . 665 Ellen A. Cappo, Arjav Desai and Nathan Michael Vertex: A New Distributed Underwater Robotic Platform for Environmental Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679 Felix Schill, Alexander Bahr and Alcherio Martinoli Author Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695 Contents xix
- 24. Abstracts of Invited Keynote Presentations Material-Integrated Intelligence for Robot Autonomy Prof. Nikolaus Correll, University of Colorado Boulder, USA Advances in miniature electronics, distributed algorithms and manufacturing technology have enabled a new generation of smart composites that tightly integrate sensing, actuation, computation and communication. Such “robotic materials” are inspired by multifunctional natural structures such as the skin of the cuttlefish that can change its color and patterning, bird wings that can change their shape, or the human skin that provides tactile sensing at high dynamic range. I will describe a series of recent results that best illustrate the benefits of material integrated com- putation: high-bandwidth sensing for texture recognition and localization in artifi- cial skins, distributed optimization for controlling shape change, distributed classification for recognizing gestures drawn onto a modular facade, and feedback control of soft robotic actuators. I will then describe current challenges in robotic grasping and manipulation, and demonstrate how robotic materials can provide critical sensing and control during a series of manipulation tasks with applications to warehouse automation, manufacturing and lab automation. Coordination, Cooperation, and Collaboration in Multi-Robot Systems Prof. Vijay Kumar, University of Pennsylvania, USA The central challenge in multi-robot systems lies in the synthesis of collective behaviors which enable group performance that exceeds the ability of individuals. We explore three different paradigms for collective behaviors. At a fundamental level, coordination is beneficial when individuals are confronted with a task that they can complete but can do so more efficiently as a group. Cooperation refers to xxi
- 25. the ability of robots to accomplish tasks they could not have completed on their own. Collaboration is useful for groups with different types of robots with diverse capabilities and tasks which cannot be completed with a single type of robot. This talk will discuss biological inspiration for these paradigms, mathematical frame- works, and resilience in collective behaviors with applications to ground and aerial robots. Go to the Bee and Be Wise: Swarm Engineering Inspired by House-Hunting Honeybees Prof. James A. R. Marshall, The University of Sheffield, UK Distributed autonomous systems are likely to become increasingly important for robotics and other applications, due to their potential for resilience, scalability,and flexibility. However, designing grouplevel behaviors that are implemented by simple individual-level rules operating with local information is an inherently hard problem, and guaranteeing properties of that behavior is even harder. For example, search techniques and formal methods applied to swarms both rapidly fall foul of the curse of dimensionality as number of agents increase. However natural selection has successfully designed such systems repeatedly, and tools from the natural sciences have rigorously described the behaviour of very large systems of interacting components. In this talk, I will recount how observations of house-hunting honeybees led to the design of a new class of distributed decision-making algorithm, and its deployment on hundreds of small and simple robots. Rather than simply imitating nature, however, the algorithm’s principled development requires the integration of concepts and techniques from areas as diverse as behavioural ecology and statistical physics. Robust Human Control of Multi-Robot Swarms Prof. Katia Sycara, Carnegie Mellon University, USA As robotic platforms become cheaper and more reliable, multirobot deployment becomes possible and desirable. Since complete robot autonomy for these deployments is not yet possible, the presence of a human operator is necessary. Multiple human studies have shown that cognitive limitations prevent effective human control of multi-robot systems of tens of robots. Another difficulty is that many different types of human interactions may be necessary to maintain and control multi-robot systems. Additionally, the coordination scheme of multiple robots can vary which has consequences on the operator’s difficulty of control. We have developed a characterization of human-robot tasks, and appropriate human xxii Abstracts of Invited Keynote Presentations
- 26. robot interaction modes, based on the task's cognitive complexity of control. This scheme helps explicate the forms of control likely to be needed and the demands they pose on human operators. This talk will present two lines of research following from this characterization. The first evaluates the potential for using scheduling techniques to improve the performance of systems in which operators must attend to multiple independently operating robots. The second presents challenges and results pertaining to human control of autonomously cooperating robotic swarms. Abstracts of Invited Keynote Presentations xxiii
- 27. Part I Distributed Coverage and Exploration
- 28. A Probabilistic Topological Approach to Feature Identification Using a Stochastic Robotic Swarm Ragesh K. Ramachandran, Sean Wilson and Spring Berman Abstract This paper presents a novel automated approach to quantifying the topo- logical features of an unknown environment using a swarm of robots with local sensing and limited or no access to global position information. The robots ran- domly explore the environment and record a time series of their estimated position and the covariance matrix associated with this estimate. After the robots’ deploy- ment, a point cloud indicating the free space of the environment is extracted from their aggregated data. Tools from topological data analysis, in particular the concept of persistent homology, are applied to a subset of the point cloud to construct barcode diagrams, which are used to determine the numbers of different types of features in the domain. We demonstrate that our approach can correctly identify the number of topological features in simulations with zero to four features and in multi-robot experiments with one to three features. Keywords Unlocalized robotic swarm · Stochastic robotics · Mapping GPS-denied environments · Topological data analysis · Algebraic topology 1 Introduction Many potential applications for robotic swarms, such as environmental monitoring, exploration, disaster response, search-and-rescue, and mining, will require the robots to operate in uncertain environments. Constraints on the robots’ onboard power may preclude the use of GPS and inter-robot communication, and even if the robots are R. K. Ramachandran · S. Wilson · S. Berman (B) School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA e-mail: spring.berman@asu.edu S. Wilson e-mail: sean.t.wilson@asu.edu R. K. Ramachandran e-mail: rageshkr@asu.edu © Springer International Publishing AG 2018 R. Groß et al. (eds.), Distributed Autonomous Robotic Systems, Springer Proceedings in Advanced Robotics 6, https://doi.org/10.1007/978-3-319-73008-0_1 3
- 29. 4 R. K. Ramachandran et al. equipped with localization devices, they may be deployed in GPS-denied environ- ments (e.g., indoors or underground). Despite these constraints, the robots may be required to map their environment in order to perform desired tasks. For instance, the robots may need to identify target payloads to transport or obstacles and hazardous regions to avoid. Since the robots will have limited sensing and computational capa- bilities, it would not be feasible to implement existing techniques such as occupancy grid mapping [24], simultaneous localization and mapping (SLAM) [21, 24], and Probability Hypothesis Density (PHD) filtering [27] to address this problem. Asaninitialsteptowardconstructingamapwithmetricinformation,wepresentan automated method for computing the number of topological features in an unknown domain from data obtained by a swarm of inexpensive robots with local sensing, no inter-robot communication, and limited or no access to global position information. The features represent obstacles or other regions of interest that robots do not pass through. The data consist of robots’ position estimates and the covariance matrices of these estimates, recorded by the robots during random exploration of the domain. The robots collect this data autonomously and independently during their deployment, without relying on input from a supervisory agent. We assume that after a set period of time, the robots navigate to an easily identifiable landmark (e.g., a beacon), where they transfer this data to a central computer. The computer then processes the data from the entire swarm to extract a point cloud that covers the domain’s free space and applies tools from Topological Data Analysis (TDA), namely persistent homology, to identify the numbers of different types of topological features. Our approach scales with the number of robots and is robust to the failure of a small portion of the swarm. Although topological mapping has been extensively studied, TDA has only recently been applied in robotics for environmental characterization. For a scenario with a single robot, [7] presents a method for topological SLAM that encodes the topology of the environment in a generalized Voronoi graph. Few works address the problem of mapping an environment using a robotic swarm with limited sensing, no inter-robot communication, and no global localization. In [19], we presented an opti- mal control approach to mapping a GPS-denied environment with a robotic swarm using a partial differential equation model of the swarm population dynamics. This strategy works best when the domain contains only a few sparsely distributed fea- tures, whereas the approach presented here can be applied to domains that are more densely populated with features. In [20], the authors propose an algorithm that covers the free space of the environment with robots and then constructs an approximate generalized Voronoi graph of the covered region. This algorithm requires the robots to communicate with a central server that commands their actions. In contrast, our approach does not require a centralized decision maker during the robots’ operation. Alternatively, [13] obtains a simplicial approximation of a region of interest as a topological map using dual pairs of nerves that are constructed using relevant vis- ibility and observation covers. Contrary to our strategy, [13] requires the robots to have the ability to detect and maintain a record of landmarks in the domain, such as obstacle corners and edges. The mapping approach in [8] is similar to ours in that it generates a point cloud of the domain’s free region and uses persistent homology to compute topological features in the environment. However, unlike our strategy, this
- 30. A Probabilistic Topological Approach to Feature Identification … 5 approach requires each robot to have an identification label that can be recognized by other robots. The paper is structured as follows. Section2 introduces the tools of TDA that are used in our methodology. Section3 presents the problem statement and describes assumptions about the robot capabilities and motion model. Our approach for extract- ing topological features of the domain from the robots’ data is discussed in Sect.4. Sects.5 and 6 validate our approach with simulations and multi-robot experiments, respectively. Finally, Sect.7 concludes the paper and proposes future work. 2 Background Topological Data Analysis (TDA) [5] is an emerging field that aims to provide algo- rithmic and mathematical tools for studying topological and geometric attributes of data. The fundamental idea underlying TDA is that data has an inherent shape that encodes important information regarding the connectivity of the data and yields insight into its global structure. TDA exploits the mathematical framework of alge- braic topology [15], especially the concept of persistent homology [9], to characterize the topological structure of data. In many applications, data is obtained as a point cloud consisting of noisy samples of an intensity map in a Euclidean space. Prominent topological features of a point cloud can be computed using TDA and presented in the form of compact representations such as persistence diagrams [10] and barcode diagrams [11]. TDA has been extensively applied to problems in computer vision and image processing [23], sensor networks [6, 14], robotics [4, 18], localization [22], and map comparison [3]. We provide a brief introduction to persistent homology, which is central to our mapping methodology. More detailed treatments of the associated theory and com- putations are given in [10, 16, 28]. Persistent homology is a method of analyzing the correlation of homological information gathered across different scales. This tech- nique enables the identification of topological features that are present over a large range of scales, as opposed to those which are only temporarily present (short-scale features). Homology is a robust tool that facilitates the study of global attributes of spaces and functions from local computations on noisy data. A topological space T can be associated with a collection of vector spaces called homology groups, denoted by Hk(T), k = 0, 1, 2, ..., dim(T) − 1, each of which encodes a particular topologi- cal feature of T. In persistent homology, these features are characterized using Betti numbers, which are the ranks of the homology groups. These numbers are topo- logical invariants. The kth Betti number of T, denoted by βk, is the rank of Hk(T) and represents the number of independent k-dimensional cycles in T. For example, if T ⊂ R2 , then β0 is the number of connected components in T and β1 is the number of holes in T. If T ⊂ R3 , then β0, β1, and β2 are the numbers of connected components, tunnels, and voids in T, respectively. In a typical TDA application, a finite set of samples from a space M is available. These samples, along with the metric associated with M, comprise the point cloud
- 31. 6 R. K. Ramachandran et al. C of the space. In TDA, the metric is used to map C onto a collection of simplices called a simplicial complex. Simplices are combinatorial objects constructed from the subsets of C. A k-simplex σ = [v0, v1, ..., vk] is an ordered list of k +1 elements {v0, v1, ..., vk} ∈ C, called vertices. The simplicial complex provides a discrete repre- sentation of the underlying topological space using a combinatorial structure that can be represented algebraically using linear operators (matrices). It is this combinatorial structure that permits us to develop algorithms for homological computation. There are various ways to build a simplicial complex from a point cloud. The simplest way is to choose a parameter δ > 0 and add a k-simplex to the simplicial complex if every vertex in the simplex is within a distance δ from every other. The simplicial complex constructed in this manner is called the Vietoris–Rips complex [12] or Rips complex for short, often denoted as Rips(C, δ). For large datasets, the number of simplices in the simplicial complex can be enor- mous, making the computations highly inefficient. We reduce the computational requirements by choosing a subset of the point cloud consisting of landmark points, denoted by L ⊂ C, as vertices for the Rips complex. These landmark points were selected using a greedy inductive selection process called a sequential max-min algo- rithm[1]. Inorder tocomputepersistent Betti numbers, werequireafiltration, defined as a family of Rips(C, δ) parametrized by δ such that Rips(C, δ1) ⊆ Rips(C, δ2) for all δ1 > 0, δ2 > 0 where δ1 ≤ δ2. The persistent topological features of T over multiple values of δ can be identified using a barcode diagram, which is a graphical representation of Hk(T) in terms of the homology generators. A barcode plots a set of horizontal line segments on a graph whose x-axis spans a range of δ values and whose y-axis depicts an arbitrary ordering of homology generators. The numbers of arrows in the barcode for dimension 0 and dimension 1 indicate the numbers of connected components and features in the domain, respectively. A barcode diagram can be computed automatically using algorithms that find the homology generators of the homology that is constructed on a point cloud. Figure1 illustrates a barcode diagram that is obtained from an example point cloud. 3 Problem Statement We consider a scenario in which N robots are deployed into a bounded, unknown, GPS-denied 2D environment in order to collect data that can be used to determine the number of topological features in the domain. The robots have local sensing capabilities and can identify features and other robots at distances within their sensing range to perform collision avoidance maneuvers. Each robot is equipped with a compass and wheel encoders, which enable it to estimate its position and orientation with uncertainty. The robots perform correlated random walks in the domain, avoiding features and other robots. During its motion, each robot estimates its position in a global reference frame using its onboard odometry and a Kalman filter. At fixed time intervals, the
- 32. A Probabilistic Topological Approach to Feature Identification … 7 Fig. 1 An example barcode diagram of a filtration formed from a Rips complex. βk(δi ) is the number of horizontal segments in the barcode for Hk(T) that intersect the dashed line at δ = δi robot records its estimated position and the covariance matrix corresponding to the uncertainty of the estimate. After a time span T , all robots travel to a common location where their stored data is retrieved and processed. We assume that T is sufficiently large for the robots to thoroughly cover the domain and that the robots have sufficient memory to store the data that they obtain during their deployment. The robots follow the motion model described in [25]. Each robot has a con- stant translational speed v and an orientation θ(t) at time t with respect to a global frame. We define a robot’s velocity vector at time t as V(t) = [vx (t), vy(t)]T = [v cos(θ(t)), v sin(θ(t))]T and its position vector as X(t) = [x(t), y(t)]T . The displacement of a robot over a time step Δt is given by X(t + Δt) = X(t) + V(t)Δt + W(t), (1) where W(t) ∈ R2 is a vector of independent, zero-mean normal random variables that are generated at time t to model the randomness in the robot’s motion due to sensor and actuator noise. At the beginning of a time step, each robot generates a random number between 0 and 1. If this number is below a predefined threshold pth, the robot randomly chooses a new θ(t) ∈ [−π, π]. At time t = 0, the start of a deployment, each robot is assigned the parameters v and pth and obtains accurate measurements of its position X(0) and orientation θ(0). We consider two types of scenarios. In Type I scenarios, robots receive accu- rate estimates of their global positions when they are close to the boundary of the domain. For example, robots on the exterior of a building will have access to GPS measurements that are unavailable to robots inside. In Type II scenarios, robots do not receive global position updates anywhere in the domain, which may for instance be located underground or underwater.
- 33. Discovering Diverse Content Through Random Scribd Documents
- 34. burnt rubber. Everywhere they are cutting the dried rubber, which looks like great cheeses, chopping it, packing it, carrying it and loading it on vessels. The Amazon district dominates the rubber market of the world. Pará and Manaos are the greatest rubber exporting ports of that district. From these cities the rubber buyers make their expeditions into the very heart of the Amazon, and its many tributaries are nearly all the home of rubber gatherers. From these centres the Indian gatherers make their expeditions by canoe, and through almost trackless forests to the trees which they are tapping. These trees do not grow in clumps, but one will be found here, another there, and oftentimes these single trees are at a distance of several hundred yards from each other. The amount of crude rubber that the native can gather depends on how close the trees may be to each other. Upwards of one hundred rubber-bearing trees, vines and shrubs have been classified; but the one known as the Hevea is the rubber tree par excellence of Brazil. It is indigenous to the Amazon and its tributaries. Trees are oftentimes found which are as much as twelve feet in circumference, but those are exceptional. They require an abundance of moisture, and it is only in the thick forest, where the necessary moisture is constant and abundant, that they will reach this extraordinary size, although the trees can be successfully cultivated. It is quite probable that thousands of these trees are still undiscovered, and perhaps large districts still await development; but it is equally certain that the rubber prospector has threaded his way through thousands of miles of Amazonian jungle in his search after this profitable article of commerce. The present unprecedented prices have bestirred the exporting firms to feverish activity. Sections of hitherto unpierced forest are now being treaded by the prospector, with his Indian guides busily engaged in cutting a path through the dense undergrowth and labyrinth of vines. The howling of the enraged beasts thus disturbed in their lairs, the fear of poisonous snakes, the dread of the fever-laden mosquito, the annoyance of troublesome insects are nothing, with the price of rubber soaring upwards towards three dollars per pound. An American rubber expert, who recently visited the Amazon rubber camps, says: “The past year more than seventy thousand tons of crude
- 35. rubber, having a value approximating $300,000,000, were produced, of which forty thousand tons came out of the Amazon River. This was wholly wild rubber, gathered almost entirely from a belt extending along the Amazon and its tributaries, and running less than three miles into the interior. The vast forest beyond these borders is substantially untouched; but with the building of the railroad around the falls of the Madeira, which will be completed in 1911, with the building of roads through the forest connecting up rivers, and with the introduction of the gasoline boat, vast districts heretofore inaccessible will be brought within the reach of the rubber gatherer; and, while the gain in production each year has been approximately but ten per cent. over the previous year, there is no question that this percentage will increase largely from this time forward.” It is not the sap of the tree that produces the rubber, but a juice which is yielded by the bark. As it flows this juice has the appearance of milk, and acts in much the same way. If left to itself it will separate into a lower fluid and a surface mass like cream, and this is the so-called india-rubber. Less than fifteen per cent. of this “cream” in the product of the tree is unprofitable and does not pay for the working. Various ways have been devised to separate the rubber by processes of coagulation. The native method has always been by a smoking heat, but in some places chemicals are used; again separators, similar to those employed in butter making, have been introduced with good results, so it is said. The method and care used has a very marked influence on the price and value of the crude rubber in the markets. The heating by smoke is generally considered to produce the cleanest and purest form of rubber for commercial export. The tapping of a rubber tree is a seemingly simple operation, and yet it requires considerable skill to so tap a tree as to produce the maximum of sap, and inflict the minimum of injury to the tree. A tree properly treated will stand continual tapping for twenty years, while a tree abused might die after two or three seasons. Hence it is to the interest of all to preserve the life of the tree. The tapper first affixes a small cup to the tree, and then with a wedge-shaped axe makes a gash in the bark, being careful not to penetrate the wood. This operation is repeated at intervals of a foot in a line around the tree. Into these cups the milk flows slowly. The next day a row of incisions is made just below
- 36. the first, and so on until the ground is reached. A good tree will yield up to a height of at least twenty feet. An expert can tap a hundred trees a day, provided that they are close together. The sap, which is collected once each day, is then brought to the camp. Heat is then applied and the crude rubber is made into roughly-shaped balls of different sizes. The buyers usually cut these in two in order to see that no extraneous substance has been placed inside to give weight. Stones have frequently been found moulded in with the rubber, and stones are easier to gather even along the Amazon than rubber. Many plantations of rubber trees, principally of the Maniçoba species, which will grow on higher and drier lands of the interior, have been set out in Brazil, but their production is very small when compared with that of the dense Amazonian forests. Of the other valuable trees of the Amazon basin Agassiz says: “The importance of the basin of the Amazons to Brazil, from an industrial point of view, can hardly be over-estimated. Its woods alone have an almost priceless value. Nowhere in the world is there finer timber, either for solid construction or for work of ornament, and yet it is scarcely used even for the local buildings, and makes no part whatever of the exports. The rivers which flow past these magnificent forests seem meant to serve, first as a waterpower for the sawmills, which ought to be established along their borders, and then as a means of transportation for the material so provided. Setting aside the woods as timber, what shall I say of the mass of fruits, resins, oils, colouring matters and textile fabrics which they yield?” These words of this great naturalist, although written years ago, are just as true to-day. At least one hundred and fifty varieties of valuable hardwood timbers have been found in these forests. As mahogany and other better known woods become scarcer, these woods will certainly find a market.
- 37. A NEW SETTLER IN THE JUNGLE. The great state of Amazonas, which is more than two-thirds as large as the United States east of the Mississippi, is an empire in itself. It is difficult to predict what may be its future. Some scientific men say that civilization will again be centred in the tropics; if so, then here will be the future Europe. Any prediction would be only guesswork, for no man with only human foresight could look into the future and foretell the development. The possibilities are visible to even the shallow observer; the uncertain trend of civilization no one can with certainty prognosticate. Nature is kind, if her laws are obeyed, and the white man endures the climate better than his copper-coloured brother. It would be the lazy man’s paradise, for it takes little labour to provide the simple wants. The only difficult task is to fight nature in her prodigal growth. The struggle of the northern farmer with weeds is an infantile task in comparison with the constant fight against every kind of growth in this climate. It would be a hopeless task for one man, lone handed and without means, to locate in this wilderness and attempt to carve out his fortune. Goodly sized colonies would do better, and, by their energetic
- 38. and united efforts, nature would be conquered and compelled to contribute of her bounty to the welfare and support of man. Outside of Manaos and a few small towns and settlements the population of the state of Amazonas consists almost entirely of Indians. One industrious writer has listed nearly four hundred separate and distinct tribes. Many of these are extinct, or practically extinct, but a large number of distinct tribes are still found on the different rivers that have widely divergent habits and physical characteristics. A few of these tribes live a retired existence in the forests, but most of them mingle with the white people, and are employed by them in gathering rubber or other products of the forests. The skin of the Indians is a coppery-brown colour. They are of a medium height, but have not the high cheek bones of the North American Indian. Like the latter, however, they are undemonstrative, and do not betray their emotions of joy and grief, wonder or fear. They will undoubtedly be driven out and disappear as the white race settle in the tropics, for their inflexible character prevents them from adapting themselves to changed conditions. Although these Indians have dropped cannibalism, and other inhuman practices, they are still simple children in their customs and beliefs. They live as their ancestors have lived for centuries, have adopted few of the conveniences or luxuries of civilization, and live a hand-to-mouth existence. Religious holidays are observed with a strange mixture of superstition. Their idea of a holiday, whether religious or secular, is “bonfires, processions, masquerading, confused drumming and fifing, monotonous dancing kept up hour after hour without intermission, and, the most important part of all, getting gradually and completely drunk.” They are kindly disposed toward aliens, and are as hospitable as their circumstances permit. The Tupi-Guarini language is generally spoken, or at least understood, and this has been reduced to written form by the Jesuit clergy.
- 39. CHAPTER X THE PEOPLE AND THEIR CHARACTERISTICS The Brazilian people are made up of three distinct races: Europeans of every nationality, but most of Latin origin, Indians and negroes, the latter two nationalities being more or less mixed in the process of assimilation, and distributed all along the seaboard and the rivers, from the Amazon to the Paraná. In Brazil there is no race problem or antagonism between white and black, or Indian, and the hopeful ones say that in course of time not only all race distinctions, but even colour distinction, will disappear, and be merged in the new Brazilian type. The pure Indians are now found only on the Amazon, the headwaters of the Paraguay, and the sections remote from the railways of such states as São Paulo, Paraná, Bahia and others. Most of them were never the bloodthirsty race that our own redskins were, although a number of the tribes were cannibalistic in their practices. The number still existing is placed at about six hundred thousand. There was no regular spreading of civilization and population, but it was done through the sporadic settlement of advancing posts which were pushed out into the wilderness. They were at first armed against the Indians, who were then hostile, but most of the aborigines were finally subjugated, and gathered into settlements by the conquerors. These settlements formed the nuclei about which the towns began to grow. As there were few European women in the country, the Portuguese took wives from among the conquered people, and such a connection was not considered a mesalliance, even by those of good birth. From these alliances arose the mixture of Indians and Europeans, which runs through many of the very best families in Brazil. In the state of São Paulo, for instance, this mixture became very marked, and produced an almost white race as the strain of Indian blood became less. It was from this race that the original “Paulistas” sprang, who distinguished themselves among the Brazilians for their bravery in driving the savage Indians from the coast, and later by their enterprise
- 40. and administrative capacity. I met one of these men in that state who was a wealthy fazendero, and a graduate of one of the best schools in our own land. I was impressed by his courtesy and intelligence, and finally asked him from what nationality he was descended. He said that his ancestry were Portuguese and Indian. “And,” he then added, “I am proud of the Indian blood in me.” From the way he said it, it was plain to be seen that he meant it; and such is the feeling of all those who have that mixture. Some of the very best men in that and other states have at least a slight trace of the aborigine blood in their veins. NEGROES IN BRAZIL.
- 41. The negroes, just as in our own land, were originally brought to Brazil and sold in bondage. The first slaves were imported into the state of Bahia in 1574. Just seventeen years later the official records give the population of that settlement as two thousand whites, four thousand negro slaves and six thousand civilized Indians. This will give a little idea of how rapidly the negroes were brought into the country by the slave traders. Great sugar plantations were worked, and on these were employed the cheap labour. The black slaves so exceeded in number the whites that insurrections broke out in many places. In Minas Geraes, for instance, out of a population of fifty thousand in the early part of the eighteenth century, thirty-five thousand were negro slaves, and most of these recent imports. Some of the whites were so fearful of their own lives, that the governor petitioned the King to put into execution the “Black Code,” which meant that the right leg of a fugitive slave might be cut off and a wooden one substituted. Thus, by terror, the excess of blacks was kept in subjection. The proportion of black population is much greater in the northeastern states than elsewhere. As one journeys south they become less numerous, until, when you reach the extreme southern states, they are uncommon. In the state of Bahia, those with a negro admixture far outnumbered the whites. This is due not only to the fact that slavery was first introduced there, but also because it was sooner abolished in that state, and fugitive slaves escaping from the coffee plantations fled there, just as they did to our own Northern states. Those who were able to buy their freedom in other states went there as well as those who were voluntarily freed by their masters, as thousands were all over Brazil. In Minas Geraes perhaps one-third of the population have negro blood in their veins. When slavery was finally abolished, in 1888, there were perhaps seven hundred and fifty thousand slaves in the empire, the most of these being held in the coffee producing states. In São Paulo to-day the negro population is very small, as it is said that the former slaves soon became decimated by the excesses in which they indulged when freedom was gained. In the whole republic perhaps very near to one- half the entire population has at least a trace of negro blood in their veins. The mixture is very marked in the north, and down as far as Rio de Janeiro, and almost to São Paulo. There is, however, no race
- 42. prejudice that I could perceive. In schools I saw kinky-haired boys and girls side by side with the whites, and in all public places they mingled freely. Negro lawyers and doctors appeared to be patronized by the whites, and their families seemed to have friends among all classes. Officially, at least, there is no distinction, and men have occupied the highest offices in the republic, who unmistakably had a trace of the negro blood. Americans, who live there, as well as some native Brazilians, tell me that there is a growing prejudice among those free from the negro blood against that race, and even the slightest mixture of it, until it has now become very noticeable in many ways, and is even making itself felt in political circles. I am making this statement solely upon the authority of those who live there, and ought to know better than a traveller; but, as for myself, I saw no evidence whatever of such a state of public sentiment. Says Dr. Hale in his book, “The South Americans,” “I was invited one evening to a small dinner-party at which we were to meet Senhorita X ——, a young lady freshly launched into society, whose musical talent was exceptional, even in this land naturally so gifted with love of both poetry and music. I was the only one of the guests who had not met her, so that she was smothered with greetings before I was presented; but when my turn came, I was astonished to find before me what we would call a mulatto—kinky hair, thick lips and prominent teeth. There was not the least trace of embarrassment in her or the rest of the company. She sat opposite me at table, played for us later some brilliant piano pieces, and kissed all the ladies good-bye with so much ease that was absolutely impossible to conceive any difference among us on account of race.” The next largest foreign element is the Italian, of whom there are two million or more. They readily adapt themselves to Brazil, because of the similarity of customs and language. They are frugal and industrious, and are gradually acquiring wealth and power. A great influence has also been wielded by the German colonists who flocked to Southern Brazil in great numbers, about the middle of last century. There are perhaps nearly one-half million of this stock. They have not progressed as have the Germans in the United States, perhaps because a living came too easily, and nature was too bountiful. The majority of them went to Brazil after the revolution of 1848, and one can trace many of the settlements
- 43. by the names of the towns. They do not intermingle or intermarry with the Brazilians like the other colonists, and one can find whole communities where no one understands the Portuguese language. They are citizens of Brazil, and yet take little interest in the body politic, neither caring for the position of alderman or policeman. It is the Portuguese element in Brazil, of course, that are the most interesting, and there is at least a remnant of the pure Portuguese left. And they have many good and excellent qualities. As a race they frequently lack what Americans term the practical element, but they have some of the finer traits, frequently missing in our own people. They have an innate courtesy which is sometimes almost overwhelming. If the same thing was done by an Anglo-Saxon, in the same profuse manner, it would be looked upon as overdone; but, coming from a Brazilian, it is done with such a grace and smoothness that seems only natural. You are greeted with an exquisite courtesy, especially after one or two meetings, and the parting is a series of courtesies. You shake hands about half a dozen times before finally separating, then pause and turn as you reach the door and make a final bow before leaving the room; and this final courtesy is always awaited by your host. If friends separate, or meet after an absence, they fall into one another’s arms and mutually pat each other on the back as a mark of affection. This is never done upon first acquaintance. It is a slow ceremony when there is a large list to be greeted, but it is faithfully gone through with; first a hand shake, and then the embrace if the intimacy warrants it. The street car conductor hands you your ticket with a little courtesy, and even the hotel servant, and they are always men, finds time to say obligado (much obliged), when you hand him the gratuity he expects as a matter of right. The carigador at the station, who carries your baggage to the train, may haggle with you over the price, but when the affair is settled he courteously tips his hat and wishes you a bom viaje, which means “a pleasant voyage.” If you remove your coat on the train, or enter a first-class car without wearing a collar and tie, the conductor reproves you with a little courtesy, as though he was performing a very unpleasant duty. The clerk in the store never hurries you in making your purchases, but patiently places himself at your disposition. And so it is as you travel all through the country, there is courtesy present everywhere, and you can not help but like the people for these traits.
- 44. LABOURERS’ HOMES ON A PLANTATION. They might also teach us something in their philosophical outlook upon life. The doctrine of “don’t hurry” and “don’t worry” is deeply rooted, and gives them greater enjoyment in life than among a race whose nerves are continually on edge. They resent any assumption of superiority, but recognize freely and generously the good qualities of the Anglo-Saxon. There is a lax moral tone on the part of the men which could be much improved, and which would greatly benefit the country at large. In the homes that I visited excellent taste was shown in the furnishing and decorations. There was only one arrangement that grew painfully monotonous. In the reception room a couch was always placed against the wall, and the chairs for guests invariably placed at right angles to this, a row at each end. This gives the host or hostess a chance to see each guest, and the favoured one is invited to share it with her, or possibly to occupy it alone. The chairs are oftentimes stiff and uncomfortable, but it is bad taste to move them, or twist around in them, as Americans are often accustomed to do. The house is yours for
- 45. the time being. As one man told me in broken English, “your house” and “your friend.” And it was my house, at least I was welcome in it; and he was my friend, I am pleased to say, for he proved it. When you are going away in Brazil, your friends always accompany you to the station, no matter how far away or how early in the morning. I must admit it is a pretty custom, and makes you feel that friends are a good thing to have. I have had Brazilian friends, of only a few days’ standing, perform this little courtesy, men of prominence and influence, and I confess that it reaches a tender place in my heart. The Brazilian women are handsome in their youth. Their bright eyes and dark features at that age are very fascinating. Especially in Rio their physique is much better than that of the men, for the “stronger sex” in that city are mostly narrow-shouldered and rather thin-chested. The women dress with good taste, but their styles have no uniqueness about them, for they wear the same high-heeled, uncomfortable-looking shoes, and the same large Parisian-shaped hats that have driven men to despair the world over. As their years increase, however, they have a tendency to become stout, due perhaps to hearty eating and lack of exercise. I must say that the Brazilians are particularly fond of eating, and in this hot climate will devour much more food, and especially meat, than those from colder climes; and, in addition, they seldom eat the noon breakfast, or dinner, without at least half a bottle of light wine of some kind. At Rio, and in Northern Brazil, the women are subject to all the social restrictions that have ever been the lot of women in Latin countries. The young women can not go out unaccompanied by an older woman or the family servant, and in the social life there is nothing of what American women would term freedom. They perhaps do not miss this so much, for it has been the custom of the race for generations untold. At São Paulo, and some of the other southern states, there is a noticeable breaking away from the centuries-old traditions, due, perhaps, to foreign influence. There one can see even young Brazilian ladies out alone on a shopping tour; and, although there is not freedom of association among young people of the two sexes, the beginning of the change is apparent, and I would not be surprised to see even a radical change in this respect in another decade or two. The women there are beginning to feel the narrowness of their lives, and to long for the freedom which they see
- 46. the young people of other nationalities enjoy. One will likewise find women employed in some of the stores, and occasionally, in other public positions in the cities of that state. It is true that political ideals in Brazil are not so lofty as they should be. If the reports of investigation committees are true in our own land, however, our own stables need a little looking after. There is undoubtedly more “graft” in Brazil than with us. Nevertheless, the Brazilians are not without ideals. The development of the artistic in parks and buildings is a convincing proof of this. The officials demand work to be up to specifications, and then want their “graft” to be over and above this, instead of the American practice of “skinning the job” to accomplish the same end. This is their system, and there is generally not so much coarse juggling as sometimes happens with us. Bankruptcy is not so common as with us, and bills contracted by private individuals are generally paid. The men are reprehensible in their private conduct, but the women are generally good. Said an American to me, who has lived in that country for forty years, and who is the best judge of Brazilian character that I know: “The Brazilian women, those who have not the mixture of negro blood, are good and pure, and in them lie the great hope of the race.” They are domestic, are the mothers of large families, and nowhere is there a sincerer love for their children shown than by these Brazilian women. In Rio there is a fast set, just as there is in every large city where there is wealth, and an idle class, and where every opportunity exists for the indulgence in vice. In the lower classes, and there are practically only two classes in Brazil, looseness in the sexual relation is very common and the percentage of illegitimacy is high. It is not looked down upon, and neither the unfortunate children nor their mothers receive social ostracism. The upper classes of the Brazilians are a well educated and cultivated people. Most of them have been schooled in France, and speak the French language almost as fluently as their own. In Paris there is always a goodly sized Brazilian colony, and the boats passing between Rio and Europe always carry a number of Brazilians to and from that European capital. They find the atmosphere of the French capital more congenial, and full of the simpatica which means so much to the Latin people. The
- 47. girls who go abroad for education are all sent to the convents of France, but many boys are now sent to schools in the States, especially for a technical education. Those who do go come back enthusiastic over the United States, and many of them bring back American wives, much to the discomfiture of the parents. An aristocracy exists which can yet be traced, and it is an aristocracy of wealth. It divides, with a sharp distinction, the aristocracy from the labouring element. It is perhaps unreasonable to expect the classes developed by a monarchical form of government to disappear so soon, for the spirit was imbued in the dozen or more generations preceding the present one. Among that class it was considered a disgrace to labour with one’s hands, and this fact has made politics and the holding of political positions a profession. This weakness in politics is, in my opinion, one of the evils of Brazil. It becomes a business and a passion with the men, even in a more intense degree than in our own land. The young man must first secure the title of doctor, and every professional man, physician, lawyer, civil engineer, teacher, etc., receives this title.[1] Then he must obtain some government appointment. Finally, when his own prestige becomes great enough, he seeks election to some office. To politics can be blamed the lack of advancement in many lines. Said one of the wealthiest and most progressive business men in Rio de Janeiro, himself a Brazilian, to me: “Politics are the curse of the country. It is all words and delay. The politicians like to talk about their great country. They boast that the Amazon is the greatest river in the world, so large that the Mississippi dwindles into an insignificant stream in comparison; that Rio is the finest harbour in the world and capable of floating all the navies in existence; and that Brazil has the greatest undeveloped natural resources in the world. When any of the resources are developed, however, it is not these men who help to do it, but it is the foreigner who sees the opportunity and grasps it. Congress meets and talks politics, instead of passing the necessary legislation. They want to subsidize everything instead of giving competition a chance. I am past sixty years of age, and it has been that way ever since I can remember.” This is quite a severe arraignment of the evils of politics, but it was exemplified during my own visit. The regular session of Congress came to an end in October, and a special session was at once convened,
- 48. because the necessary appropriation bills had not been passed. This was just a few days before the special service must adjourn, and no progress had then been made. Long speeches were made, but most of the talk was regarding the two candidates for the presidency. As this was the first time in the history of the country that there had been two active candidates for this high office, the senators and deputies spent their time arguing the merits of their respective candidates. The Congress had then been in continuous session for almost nine months. Another unfortunate condition and characteristic is the dependence upon what Americans would term “pull,” or influence. Even the well qualified young man depends more upon that than upon the real qualifications he possesses. So many are looking for “soft snaps” that it becomes absolutely necessary to provide them. I heard of this from so many sources, both native and foreign, that I am fully impressed with its evil. It is even customary in educational institutions for students, who have not been diligent, to bring to their professors at examination time letters of recommendation from influential persons, stating why this particular student should be passed or given his degree. Foreign teachers soon shut down upon this method, and it has had a beneficial effect in their schools. Any work that is done under a concession must have a government inspector on the payrolls, and the man appointed is frequently one who knows nothing about the work, but draws his salary. A college must have a government inspector, who has nothing in particular to do except that he must attend the examinations, and no degree is granted without his approval. This inspector may or may not be qualified for the position, but the salary of three hundred milreis per month from the college makes it a nice political appointment, for it is practically a sinecure. The Brazilians are ambitious, but a lack of energy interferes with what they otherwise might accomplish. In many of the government departments and industries foreigners are employed at large salaries, which might just as well be filled by natives, if the young men would only qualify themselves. Very many of the agricultural schools and experimental stations are in the charge of foreigners, Americans, Belgians, French and German. They are rather fanciful and visionary in their plans, and will not begin at the bottom as is necessary. They would rather build the superstructure first, for that is the showy part. It is
- 49. perhaps the innate ambition, however, that will finally lead the country out of the rut. They are willing to be led but cannot be driven. “There is no public opinion in Brazil,” said one of the most influential and ablest men in Brazil, a man who has travelled extensively and made a study of other nations. “The masses do not think. The politicians plan and carry out things themselves and create the opinion.” This strikes me as being true. Politicians are the same everywhere, and here they have practically a free hand. A large percentage of the population are not able to read or write, and the percentage of those who do take an interest in politics is small. They say that there is no use; but it is a bad precedent. In every state there is a small clique who rule the politics of that state. If a man announces himself as a candidate for president, for instance, these wise men get together and announce their positions; and this announcement is everywhere taken without question, as the choice of the state. No political ring in the United States has ever been able to wield such absolutely despotic power as these cliques. There the voters will occasionally wake up and smash the corrupt machine, while in Brazil the elections are usually merely perfunctory occasions that must be gone through with. This does not mean that every one of these machines is bad, for many of the men who have this power use it for the benefit of the people, and have done much to advance the interests of the masses. To them great credit should be given, for, having it in their power to do absolutely as they wish, they have the courage and honesty to use this power in the interest of the people, just as much as if they had secured it from the people by a popular suffrage. Out of the eighteen million people in the country there are perhaps six hundred thousand qualified to vote, and there have never been more than four hundred thousand votes cast in any presidential election. The people enjoy play, and always welcome “festa” occasions. Holidays are numerous and all join in their celebration. Brazil has two independence days, the 7th of September and the 15th of November, which are national holidays and universally celebrated. The carnival season, however, which occurs the week preceding Lent, is the occasion of the greatest merrymaking. It lasts for three whole days in Rio de Janeiro, and, during that time, business is wholly suspended in the cities. There are processions with music, and the streets are full of people in mask and gown, who dance and sing and blow horns and
- 50. make disagreeable noises in general. Disguised in dominoes and masks they blow their horns, talk in falsetto voices, while the balconies and windows are filled with crowds of onlookers, women and children being especially prominent. Few people wear their best clothes, for it is the custom to squirt perfumed water over passers-by from these balconies. This perfumed water is contained in little leaden vials, which are sold at stands all over the city. The streets are hung with the banners of all nations, little flags and coloured lanterns, and have all the appearance of a gala occasion. THE FIFTEENTH OF NOVEMBER IN SÃO PAULO. On the last of the three days a grand procession is held. It is a procession of mounted military bands, men and women in ancient costume, immense floats, papier-mache figures, grotesque animal representations, men burlesquing women actresses, and women dressed as pages. King Carnival, upon a gorgeous throne, is always a part of the procession. The procession winds in and around one street after another, along the Avenida Central and the Beira Mar, and often takes hours to pass a given point. At night masquerade balls at the various
- 51. theatres end the gaieties. The galleries and boxes are always filled with an interested audience, but the floor is given up to revelry and suggestive dancing, which would not merit the approval of polite society.
- 52. CHAPTER XI EDUCATION AND THE ARTS The educational facilities in Brazil are not of the best in the republic as a whole. In some of the states, such as São Paulo, Rio de Janeiro and a part of Minas Geraes, the provisions are fairly good, but in none of them has the work been systematized in the same way that it has in our own land. Until the establishment of the republic the instruction was almost entirely in the hands of the church, but the duty now rests upon the various states and municipalities. Statistics upon education in Brazil are very unreliable, just as are their census reports, so that whatever or whosesoever figures are followed there will be errors. It is perhaps safe to say that not over twenty-five per cent. of the total population are able to read and write. The government has issued a volume which gives the figures of school enrolment of the various states, which is the first attempt on the part of the federal government to give educational statistics. In a few of the states, so the official report says, the estimates of school enrolment are not complete, since it was impossible to secure complete returns from some of the rural districts, but in the main they may serve to give a fairly adequate idea of the educational facilities in the republic; at any rate, they are the best figures that are obtainable. The figures include all schools, whether of public or private character, state or municipal. The total number of primary schools reported is eleven thousand one hundred and forty-seven, of which one thousand eight hundred and fifteen are public municipal schools, seven thousand and eighty nine public schools under state control, and mostly in the smaller towns and villages, and two thousand two hundred and forty-five private schools, most of which are in the larger towns and cities. The state schools, which are improperly designated as rural schools, have an enrolment of three hundred and forty thousand six hundred and ninety-seven, and an attendance of two hundred and forty thousand six hundred and ninety. The municipal schools have an enrolment of one hundred and six
- 53. thousand seven hundred and fifty-four, and an attendance of sixty-nine thousand four hundred and thirty-two. Private primary schools have an enrolment of one hundred and ten thousand eight hundred and forty- one, and an attendance of eighty-one thousand and sixty-six. Of the three hundred and twenty-seven secondary institutions twenty-nine are public and two hundred and ninety-eight under private control, the former having an enrolment of four thousand and the latter of twenty- six thousand two hundred and fifty-eight. No figures of the actual attendance at these institutions were given, but it would probably not be much less than the enrolment. If these government figures are correct, and the population is twenty million five hundred and fifteen thousand as claimed, in that same report, then scarcely three per cent. of the population may be regarded as enjoying school privileges. This estimate takes on new significance when one considers that the proportion of rural population is very high, as compared with the entire population, and shows how much less the facilities are in those sections. In the Federal District, for instance, which includes the city of Rio de Janeiro, and where the population is almost entirely urban, there is an estimated population of eight hundred and fifty-eight thousand, and a school enrolment of sixty-one thousand nine hundred and thirty-three. In the state of Alagoas, on the other hand, with an almost equal population, and where it is altogether rural with the exception of a few coast towns, there is a school enrolment of only fourteen thousand and ninety-two. The state of Pernambuco, with only one town of any size, and that the capital, has a school enrolment of only twenty-two thousand eight hundred and fifty-two, in a reported population of one million three hundred and ten thousand. More comparisons might be made, but with these explanations the reader can figure them out from the table.[2]
- 54. A SCHOOL FOR BOYS IN SÃO PAULO. The school instruction, except in the Federal District and the professional schools, is in the hands of the various states. In none of them does a compulsory educational law exist, and, if it did, the facilities do not exist to take care of those of school age who would thus be obliged to attend. As will be seen by the comparisons the provisions for instruction and the illiteracy vary much in the different states. Some of the states are richer than others, and can afford to spend more money for public requirements, and others are naturally more progressive. All of the schools in the various states are modelled on the same general plan. I have chosen those of São Paulo for illustration, because that state has made better progress along educational lines than the others, and because I made a special study of the school system of that state.
- 55. A SCHOOL FOR GIRLS IN SÃO PAULO. The schools are divided into three classes: primary, secondary and superior. The primary schools are again divided into preliminary and complementary instruction. The preliminary instruction is given in ungraded schools, and the law requires the establishment of an ungraded school in every community where there are from twenty to forty pupils of school age, although this has not always been done. Where there are six or more of these schools, a “school group” may be established, in which teaching is graded. In this state there are about eighty of these school groups. In addition there are a number of night schools where similar instruction is given to those who are unable to attend the day schools, or who have passed the school age and lacked the opportunity for an education in their youthful days. Of these there are thirty-four in the state at the present time. A few free kindergarten schools are also maintained in the capital, but this feature of instruction has not been developed much as yet. The secondary instruction is given in what are termed gymnasiums. All of these schools, whether public or private, in order to be recognized
- 56. over the country, must conform to the regulations laid down by the National Gymnasium at Rio de Janeiro. They must observe the programmes and courses of study laid down by that institution, and the student in one of these gymnasiums is given the degree of bachelor of letters, or science, after a course of study covering six years. In the state of São Paulo, there are three of these schools: one in São Paulo, one in Campinas and one in Riberão Preto. The course of study is about equal to that of the average high school in the United States, and prepares the student to matriculate in the schools for superior instruction. The so-called superior schools are those devoted to technical and professional education. For superior instruction there are in this state two institutions: the Law School and the Polytechnic School, of which the former is a federal institution, and has graduated some of the brightest lawyers and statesmen of the republic. The Polytechnic School is devoted, as its name indicates, to the teaching of the practical sciences, and is fitted with the necessary apparatus for such instruction. The school year in the public schools is generally from the first of February, or March, to the end of the following November, but the professional schools do not begin as a rule until the first of April. A model school, the Braz Grupo, is maintained in São Paulo, which is used as the name would indicate, as an example for the other schools. One school of which this state is very proud is the Normal School, which has departments for all grades from the kindergarten up. Its primary object is to prepare teachers for the work in the other schools, and in this respect it is doing an admirable work. As its accommodation is limited the students are only admitted upon special recommendation, and it is sometimes difficult for a boy or girl to secure admittance, as it is always full. The normal course extends over a period of four years, and covers a wide range of subjects. It is fitted up with a good library, a chemical laboratory, gymnasium, modelling rooms and apparatus for manual work. It has turned out several hundred graduates, of whom the proportion of women exceeds that of men in about the same proportion as they do in our own land. The director of public instruction in this state is a progressive man, and is making many improvements in the work. He made a trip to the United States in order to study the system there, and brought back a great many practical ideas. He is arranging the courses of study and
- 57. method of instruction in the schools of this state after the system in use in the United States. It cannot be done all at once as there are certain prejudices in the minds of some that must first be overcome. This process has been in operation for several years, and one can see the good results. The building was originally planned by an American lady teacher, who was brought down for that purpose. The only two modern languages taught, except the Portuguese, are French and English. This is a compliment to our tongue to have it chosen in preference to the German and Spanish, as is generally the rule. Their method of teaching the English is very practical too. This means that in the course of a few years the English language will be much more common than it is to-day. I found that the people were anxious to learn English, and those who did know it were proud of the accomplishment. Formerly they desired to know only French, in addition to Portuguese, for that was the polite language; but, as commerce has developed, the desire to know English has increased in proportion, until now all those who are able to go to the higher institutions of learning are taking up the study of English. There are a number of other institutions of learning in this state, most of them under the auspices of the various Roman Catholic orders. Some of these schools are of a very high order and are doing their share in the work of raising the standard of education. One of the best of their institutions is a large convent school for the education of girls. The most important non-Catholic institution is the Mackenzie College, which was founded by Presbyterian missionaries, but is now undenominational. At its head is the venerable Dr. Horace M. Lane, a scholarly and able man, whom I am glad to enrol as a friend. Dr. Lane first came to Brazil in 1857 as a physician, and has lived there continuously since that time, except for a period of fourteen years, during which he practised medicine in the United States. When the college was endowed with $50,000 by John T. Mackenzie, of New York, whose name it now bears, Dr. Lane was chosen president and has remained at the head ever since. The will of the above benefactor left the college a large additional sum of money. Dr. Lane understands the Brazilians as few Americans do. He is a very kindly and generous critic, and frankly tells them their faults without flattery. His candour and frankness have won him friends and the respect of all, and even of the Catholic clergy. Mackenzie College is unique in that it has never asked recognition of the government, but is
- 58. affiliated with the University of the State of New York. This institution has been in existence a number of years, and its instructors have had the pleasure of seeing many of its graduates reach positions of the greatest importance, both at home and abroad. The resident foreigners send their children there, and the Brazilians do likewise. A graduate of Mackenzie College has a recognized standing all over the republic even though it has not asked for government recognition, and placed itself under the necessity of maintaining an official inspector on its pay roll.
- 59. STUDENTS AT THE AGRICULTURAL COLLEGE, PIRACICABA. The O Granberry College, at Juiz de Fora, in the state of Minas Geraes, is another progressive North American college, under the auspices of the Methodist Episcopal Church South, that is making a reputation in Brazil. I had the privilege of attending the commencement exercises at this college, in company with the American Ambassador and his military attaché. The festa exercises, as they term it in Brazil, were attended by a very large audience. Representative citizens of the community, including the mayor of the city and the president of the Camara, which is a sort of county council, were present on the platform. This shows a truly liberal spirit, for perhaps only a very small proportion of the audience were other than Roman Catholics. This school maintains, in addition to the regular academic courses, schools of pharmacy, dentistry and theology. Their schools of pharmacy and dentistry are among the very best in the republic. A government military instructor is also kept to drill the boys and young men in military tactics, much the same as in the colleges of our own land. I was surprised to find a number of young women taking up the study of pharmacy and dentistry, for it seemed a wide departure in this land of conservativeness
- 60. and tradition, which has heretofore denied to woman that larger field granted to the sex in Anglo-Saxon countries. The generous spirit and encouragement shown to these institutions, conducted by aliens and Protestants, and the wider field granted to women, are good omens, I believe, for the future of the land. A number of states have established agricultural schools, which promise much for the future. The best one of these schools is the Escola Agricola, at Piracicaba, which is maintained by the state of São Paulo. The site for this college was presented to the state by one of its progressive citizens. The Secretary of Agriculture of that state travelled widely throughout the United States and Europe, studying places and methods, and finally decided to establish the school on the American system. He then engaged Dr. Clinton D. Smith, an American, who had been at the head of a prominent agricultural college in the United States, to take charge of the work. The faculty also include two Frenchmen, one Belgian, one Bulgarian, one Portuguese and a number of Brazilians, making quite a cosmopolitan board of instructors. The institution is housed in a large, beautiful building, and its equipment is equal to our own best institutions. The student is instructed in the analysis of soils, and the introduction of modern machinery for their cultivation; in botany, and a good course in stock raising; and in physics, even to measuring the force of a waterfall, or winding a dynamo. There is also a course in physiology, hygiene and medicine for emergencies, as well as much-needed instruction in political economy. The most practical feature is the actual work on the farm which every student is obliged to do. He must work for two hours each day in the actual occupation of handling a plow, rigging a harrow, managing a mower or reaper, and learn how to repair any of the common machines on the plantation. Students from a number of states attend the school, and many of them are sons of wealthy Brazilians. As the able director told me: “It is a good and much-needed training for a set of boys born where slavery was in existence, and in a land where to work with the hands is a sign of inferiority. The hope of the college is to exert a fundamental influence on agriculture, where monoculture is the rule and polyculture ought to be.” It will do more than that, for such instruction will have an important bearing in developing the character of these young men as well.
- 61. Portuguese writers are prolific. Few countries have produced more literature, compared with the number who speak the language, than Portugal and Brazil. The Portuguese language is especially rich in expression, and is said to be the nearest to the classic Latin of any living dialect. It lends itself easily to poetic expression, and there have been many poets. The Brazilians are fond of elaborate and flowery expressions, and this verboseness and ornate form of expression runs through their literature and public speaking. At the commencement exercises mentioned above the addresses of some of the graduates were most elaborate. Where an American graduate would have started out with “Ladies and Gentlemen,” and perhaps have added “our dear professors and honourable trustees,” the Brazilian youth took several minutes to make his introductory remarks, and pass around his compliments to the professors and other dignitaries who were on the stage. No one was omitted in the general round of compliments. Impromptu poems spring up on every and all occasions, and the recent visit of a high state official of the United States prompted more than one poetic effusion, many of which were fortunately suppressed by the committees in charge of the festivities. Brazil has produced a number of eminent writers. The best known, and perhaps most widely loved of all, is Gonçalves Diaz, who has been called the Longfellow of Brazil. He died nearly a half century ago, but his memory has been honoured by monuments and streets named in his honour, and his name has been kept green by continuous quotations from his writings. The “Song of the Exile,” written by him, has been called the “Home, Sweet Home” of the Brazilians, and is said to be quoted more than any other poem in the language. Says Mrs. Wright:[3] “No translation has ever been made which in any sense reveals the exquisite delicacy of touch in the original, or its plaintive rhythmic melody, though many attempts have been made to put it into English and other languages. Throughout the six stanzas of which it is composed, the little poem voices a heart cry of homesickness. After recounting, with childlike simplicity, the charm of his native land, its palm trees, and the sweet-voiced Sabiá, the favourite songbird of Brazil, he prays with touching pathos to be spared to return, that he may once more see its glorious palms and hear the Sabiá sing.” Diaz had received a good education in Portugal, and became a professor of history in the
- 62. college at Rio. Many of his poems have a historic basis and deal with events of history. He served on several government commissions, among which was a trip up the Amazon with a scientific commission. On this trip his health was ruined, and from that time he was an invalid to the time of his death. On his return from a trip to Europe his vessel was shipwrecked, and his remains went to a watery grave, at the early age of forty. There have been many other and excellent writers, both of fiction and poetry, in the past century, but few of them are known to the English- speaking world, as translations have not been made. Some excellent histories have been written also, which have been fostered and preserved by the Brazilian Historical and Geographical Institute. Dr. Machado de Assis is one of the most distinguished living writers, who has written both poetry and fiction. Dr. Olavo Bilac has also written many beautiful poems, and is one of the best-known writers and orators of the day. I had the pleasure of meeting him, and listening to an address by him, and it was a very pleasing address, distinguished for its purity of style. Dr. Ruy Barbosa, prominent also in political circles, has been a prolific writer in many lines. There is scarcely an important subject that his pen has not touched upon, from fiction to the intricate problem of international law. Baron de Rio Branco, a member for many years of the official cabinet, and Dr. Joaquim Nabuco, late Ambassador to the United States, who died a few months ago in Washington, are also writers of considerable merit. The press of Brazil is a strong factor in the literature of the country, as well as in the politics. Nearly every politician is a writer, and, conversely, nearly every writer is more or less of a politician. Speeches are published in full, and politics and literature fill a large part of the space in the average Brazilian newspaper. The first newspaper established in Brazil was the Gazeta do Rio, in the year 1808, and other newspapers followed soon after in many other cities. The oldest paper in the capital, as well as the most influential one to-day, is the Jornal do Comercio, originally established as the Spectator, in 1824. Its contributors have included all the leading politicians and writers since that time. It is a large and well-printed newspaper of many pages, and is well edited. O Paiz, Correio da Manhã, Jornal do Brazil, Gazeta de Noticias, Diario do Commercio, Diario de Noticias, A Noticia, O Seculo, Correio da Noite and
- 63. A Tribuna are the other leading daily newspapers in the city to-day. O Malho and Revista da Semana are weekly reviews, while O Tico-Tico and Fon-Fon are illustrated comics. São Paulo, the second city, has a dozen daily newspapers, more than the average city of the United States of the same size. O Estado de São Paulo and the Correio Paulistina are the leading and most influential ones. The Brazilian Review, a weekly journal, is the only English periodical published in the country, but there are several German and Italian publications. There are also a number of class publications and trade journals, and nearly every town and city has a local daily or weekly publication. The artistic sense is one of the essential elements of the Latin character. It has perhaps reached its highest development with the Italian race, but the Spaniards and the Portuguese also have this talent well developed. The traveller throughout Latin America can not fail to be impressed by the transplanted art that he finds everywhere in evidence. In Mexico, Central America and Peru he will find the original sense tinged with the Indian influence of the ancient races, who developed an architectural style of their own. Along the Atlantic coast of South America this element is lacking, because the Indians of that coast had not reached an advanced civilization, and lived in the crudest way. Hence the architecture of Brazil corresponds more nearly to the established schools that one will find in Latin Europe. The Latin Americans strive for beauty, and, for myself, I must say that in general I admire their style. Some of their buildings would not appear well in a cold climate, but in design and decoration they are well adapted to the country. The government buildings, the plazas, the numerous statues, all have lines of beauty that please the eye. In small towns far from the railway one will oftentimes stumble upon a church, a convent or some other building of real artistic beauty and design. These buildings in a sense satisfy the artistic hunger of the race, and they are the objects to which every resident points with pride.
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